| Summary: | Differences in price induce to use, when it is possible, low quality surimi to elaborate certain products. In this case high proportion of starch is use to maintain the gel texture. In order to reduce the caloric input of starches and to improve gelation, the addition of certain additives and the reduction of NaCl are checked with the purpose to elaborate more healthy products.
The additives tested were 0.3% sodium ascorbate (-S-) and 0.1 % cystine (-C-). Two different NaCl concentrations were used 0.3% (-A-) and 3% (-B-). Combining the addition of the two additives and the two level of salt, two types of gelation were made: at 90ºC without setting (-Q-) and at 90ºC with setting of 24 hours at 5ºC (-SQ-).
Analyses performed on gels were water binding capacity, the content of sulphydryl groups, mechanical and colour properties. It was also studied the thermal gelation profiles of the surimi pastes by dynamic thermo-mechanical analyses (DMTA) in the LVE range. Thus, storage modulus (G’) and phase angle (δ) profiles, during heating at 15° to 85°C, were obtained. In control gels (Control) made with low proportion of salt (A), the formation of SH bonds were higher than in the case of Lot B gels. When cystine or sodium ascorbate are added, the proportion of SH bonds were similar in both lots (A and B). On the other hand, breaking force increased when additives are added to both Lot A and Lot B with very similar values. Breaking deformation also increased with the additives addition, which was especially evident in high salt gels (Lot B). Gels processed with setting (SQ) , mainly in gels with more salt (Lot B), showed breaking deformation values very similar among control sample (B-control) and added with additives (B-C and B-S) because of the formation of other bonds different to SH during the setting period. In relation to the breaking deformation values, it looks like if the addition of additives in low presence of NaCl (Lot A) is of great importance in order to reach higher breaking deformation which could be considered a measure of gel stability. Concerning to water binding capacity, in Lot A and Lot B, the addition of sodium ascorbate and cystine improved the WBC in both Q and SQ gels. Colour of the gels, was modified by the addition of both ingredients. In relation to G´ and δ profiles, the addition of these ingredients in surimi pastes (A and B) rendered stronger gels than their respective controls, but their conformational stability was not improved. It happened, especially with cystine in paste B which produced gels as stronger as gels A. On the other hand, surimi pastes A produced stronger gels than pastes B.
In conclusion, in general, the physicochemical and viscoelastic properties of gels were improved by the addition of both ingredients, giving stronger gels even at very low level of salt. These results indicate that both ingredients, which do not add calories to the final gels, can be used as a good alternative for the better gelation of the low quality surimis.
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